WASHINGTON, March 13 (Reuters) - Gina Haspel, a veteran CIA clandestine officer picked by President Donald Trump on Tuesday to head the CIA, is a controversial figure, backed by many in the U.S. intelligence community but regarded warily by some in Congress for her involvement in the agency's "black site" detention facilities.

Haspel was selected as the agency's new director after the Republican president fired Secretary of State Rex Tillerson and chose current CIA Director Mike Pompeo as Tillerson's replacement.

If confirmed by the U.S. Senate, Haspel would become the first woman to head the CIA, after serving as deputy director since February 2017. Trump told reporters he has worked very closely with Haspel and regards her as "an outstanding person."

U.S. officials said that while Haspel was generally held in high regard at the CIA, her nomination raised the unwelcome prospect of greater congressional and media scrutiny of officers who are more comfortable in the dark than in the spotlight.

"This is going to reopen wounds from a decade and more ago, and also invite more oversight of both our analyses and our activities, especially if Gina is confirmed," said one U.S. official, speaking on condition of anonymity.

When she was named deputy director last year, intelligence officers who served with her and congressional officials said that in 2002, during Republican former President George W. Bush's administration, she ran a secret CIA prison in Thailand codenamed "Cat's Eye." Two suspected members of the al Qaeda militant group were subjected to waterboarding and other harsh interrogation techniques at the facility.

Three years later, still during Bush's presidency, she helped carry out an order to destroy videotapes of the waterboarding, which simulates drowning and is considered a form of torture, according to those people.

Such facilities are called "black sites" because their existence is unacknowledged by the U.S. government.

On Tuesday, some U.S. intelligence officials said reports of her alleged involvement in interrogations involving torture were false. However, they did not immediately provide details.

They did not dispute her involvement in carrying out orders to destroy videotapes of harsh interrogation techniques, which was reported in the book "Hard Measures," by Jose Rodriguez, her boss at the time, and former CIA spokesman Bill Harlow.

A CIA spokesman had no immediate comment.

Senator Ron Wyden, a Democratic member of the Senate Intelligence Committee, said on Tuesday he opposed the nominations of both Pompeo and Haspel.

"Ms. Haspel's background makes her unsuitable to serve as CIA director," Wyden said. "Her nomination must include total transparency about this background, which I called for more than a year ago when she was appointed deputy director. If Ms. Haspel seeks to serve at the highest levels of U.S. intelligence, the government can no longer cover up disturbing facts from her past."

One key Republican, Senate Intelligence Committee Chairman Richard Burr, promised to support her nomination. Saying he was "proud" of her work, Burr said he would ensure her nomination would be considered without delay.

"I know Gina personally, and she has the right skill set, experience and judgment to lead one of our nation's most critical agencies," Burr said.

Her confirmation hearing has yet to be scheduled.

"There is no question that a director leaving after a year is very turbulent for the agency," said former CIA Director Michael Hayden. "That said, leaving Gina and making her the actual director will have a very positive calming influence."

Hayden added, "I suspect other parts of the government (will) see more turbulence out of this than CIA will."

Human rights groups signaled opposition to Haspel.

"Haspel is a particularly controversial choice, given her reported past involvement in torture at CIA black sites. No one responsible for torture should be leading a federal agency, period," said Rob Berschinski, senior vice president of Human Rights First. "The Senate should use her confirmation process to send a strong signal about where this country stands on correcting the mistakes of the past."

Haspel has served in a number of undercover overseas posts in addition to her work in Thailand, including as chief of the CIA station in London and the agency's base in New York. Then-CIA Director John Brennan in 2013 named her deputy director of National Clandestine Service, but she was denied a permanent promotion in the face of congressional opposition.

(Additional reporting by Mark Hosenball and Patricia Zengerle; Writing by Yara Bayoumy; Editing by Will Dunham)